Question : Exchange 2003, DNS, MX Records and Internet Mail SMTP Connector help

Current Setup: Email is forwarded to external SMTP connector. (this is so external company can add filters/policies to our email)
Goal Setup: Bringing in our own email filtering device. Email will then come directly to us.

Network Setup: Running Exchange 2003 server running on Win 2003 which also hosts our AD, DHCP and internal DNS.  I run WHOIS and find the domain servers in listed order--it's the company that hosts our website. When I go into my Ex Sys Mgr/Connectors/Internet Mail SMTP-my settings are to Forward all mail through this connector(which is the company that filters our email for us)--as well as see the same info under Protocols/SMTP/Default--smart host.  I look through my DNS settings/Forward/domain.com and see entries for all my internal, and only a few for external. I also have TXT--v=spf1 a  and v=spf1 mx...but no mx record.

Further Background info: We are currently switching 24x7 managed Firewall vendors-the new firewall co. will have a device inhouse--rather than filter through them.

What all do I need to change/add/delete in order to make this transition as smooth as possible? Do I need to check with the whois people to make sure they have 'records' to forward my email to me? Can I just select Use DNS in the SMTP settings--and remove 'smart host' entry under protocol? Do I need to add an mx record on my DNS settings?

Answer : Exchange 2003, DNS, MX Records and Internet Mail SMTP Connector help

Use this:
http://www.kloth.net/services/nslookup.php

Set it to Any. Put in your own domain.
That will show you the name servers etc.

To check PTR records, enter your external IP address.

Simon.